1. Field of the Invention
The invention relates to a battery system including: a battery that is charged with electric power from an external power supply; and a heater for warming a battery by receiving the electric power from the external power supply.
2. Description of Related Art
In Japanese Patent Application Publication No. 2012-191782 (JP 2012-191782 A), electric power (charging electric power) from a charger that is connected to an external power supply is supplied to a battery, so as to charge the battery. In addition, the electric power from the charger is supplied to a heater to generate heat in the heater, so as to warm the battery.
In the case where an electric power supply to the heater is shut off when the electric power from the charger is supplied to the heater and the battery, the electric power that should be supplied to the heater is supplied to the battery. Even in the case where it is attempted to lower the charging electric power of the battery in this state, the charging electric power of the battery is temporarily increased in a period from a time that the electric power supply to the heater is shut off to a time that the charging electric power of the battery is lowered. Depending on an SOC of the battery, a voltage value of the battery is possibly increased to be higher than an upper limit voltage value due to the charging electric power, which is temporarily increased.